Tor gives you a random IP, it also is built to give you IPs that are shared most (bandwidth based), it focuses only on anonymity and protection of the node owners. Performance, using as proxy or stability is no priority in the Tor development.
Tor is mainly a program for residents of countries like burma, china, iran and similar where aggressive authorities monitor your activity and cut your penis (alternatively hands, legs or heads) when you do/look at something "wrong".
That is why I invented Cloakfish, it's using Tor nodes as proxies but it focuses on optimum peformance and the requirements in SEO businesses.
So when you use Cloakfish you are able to use Tor nodes noone else has used before or IPs that are used very rarely.
So while texacola is definitly right (when you use Tor to create affil accounts or post on CL you'll have no luck because of the massive abuse) Tor itself has still the potential to do that but not with the original program.
I know customers of Cloakfish use it for posting on CL successfully, also the use for account creation, cpas, paypal and EPN was reported as success multiple times to me.
For minor CL adventures it is probably not the worst tool, it will provide mixed results per post. (some require PVA, some work fine without and some will be ghosted)
If you plan to do hundred or more posts per day you'll want a private proxy solution like offered by texacola and mrtornado here on BHW.
Of course the need for a PVA might come up, at least after a few days of use on a fresh c-class it will be soft-banned by CL.
If you just need a high anonymous IP without preferences and no demands for stability, performance or previous abuse then plain Tor might be a solution. (As example to spy on competition, entering fake datails in foreign formulars etc)
Some months ago I compiled a list of different ways to change your IP and their advantages/disadvantages (http://www.blackhatworld.com/blackhat-seo/black-hat-seo-tools/39912-professional-ip-anonymity-tool-cloakfish-anonymity-discussion-thread.html) maybe of interest.